The present invention relates to a hot laminating apparatus, and more particularly to a hot laminating apparatus having a single-sided transmitting and heating roller.
Laminating apparatuses are widely used for laminating a sheet between two pieces of plastic films. A conventional laminating apparatus shown in FIG. 1(a) principally comprises two pairs of rollers, i.e. front rollers 10 and rear rollers 11, and a heating unit 12. The front rollers 10 comprise an upper front roller 101 and a lower front roller 102, while the rear rollers 11 comprise an upper rear roller 111 and a lower rear roller 112. The heating unit 12 comprises an upper heating element 121 and a lower heating element 122. The heating unit produces heat from electricity. The process for laminating a sheet material by way of the laminating apparatus is illustrated as follows. The sheet material is sandwiched between a pair of plastic films. The sandwiched structure is then fed to the passage between the upper heating element 121 and the lower heating element 122 by means of the front rollers 10, and the plastic films are heated and thus softened. Then, the sandwiched structure advances and is pressed to laminate by means the rear rollers 11 so as to bond the sheet material with the plastic films.
In the above-mentioned laminating apparatus, since the heating mechanism and pressing mechanism are separately performed by two individual units, the materials of the sheet and the plastic films should be limited to some special combinations in view of the heating and laminating timings. In addition, the laminating effect of such laminating apparatus is sometimes not satisfied, for example, due to formation of some bubbles in the resulting article.
In order to overcome the drawbacks, another laminating apparatus as shown in FIG. 1(b) was developed. Such laminating apparatus, also referred as xe2x80x9chot shoexe2x80x9d, comprises only a pair of rollers 22. The heat generated by heating plates 21 is uniformly distributed over aluminum extrusion elements 20, and radiated to heat up the rollers 22. Therefore, when the sheet material sandwiched between a pair of plastic films is fed through the rollers 22, the heating and pressing mechanisms are simultaneously performed thereon so as to avoid the problem of forming bubbles. Since heat for pressing the sandwiched structure is transferred to the rollers 22 through air gaps between the aluminum extrusion elements 20 and the rollers 22, a relatively long waiting time, for example 10-15 minutes, is required to warm up the laminating apparatus. Therefore, another laminating apparatus as shown in FIG. 1(c) was developed to solve this problem.
Please refer to FIG. 1(c). The laminating apparatus includes a pair of electro-heaters 30 disposed inside a pair of rollers 31, respectively. The rollers 31 are disposed to form a passage therebetween for passing therethrough the object to be laminated. The rollers 31 wrapping therein the electro-heaters 30 can thus quickly reach the operation temperature due to the direct heat transfer from the inner heaters 30 to the rollers 31. This laminating apparatus, although has a compact size as well as high heating efficiency, is every expensive. Therefore, the cost is high and the commercial competence is comparatively low.
Therefore, the purpose of the present invention is to develop a hot laminating apparatus to deal with the above situations encountered in the prior art.
An object of the present invention is to provide a hot laminating apparatus, which uses a decreased number of electro-heater-contained rollers and designs another relatively cheap mechanism in stead, so as to reduce the cost without decreasing the heating efficiency.
According to a first aspect of the present invention, a hot laminating apparatus having a transmission passage for passing therethrough thin films to be hot laminated, comprises: a still heating member disposed at a first side of the transmission passage for heating a first one of the thin films in contact therewith; and a transmitting and heating roller disposed at a second side of the transmission passage for heating a second one of the thin films in contact therewith, and rotating relative to and cooperating with the heating member to transmit the thin films through the transmission passage while pressing the thin films to be laminated.
Preferably, the heating member includes a heater for providing thermal energy; and a heat-transmitting element disposed between the heater and the first side of the transmission passage for transmitting the thermal energy from the heater to the first one of the thin films.
Preferably, the heater is an electro-heater for transforming electric energy into the thermal energy.
Preferably, the heat-transmitting element is made of a heat-conducting material, and the thermal energy is transmitted from the heater to the first one of the thin films in a manner of heat conduction. The heat-transmitting element, for example, is made of aluminum.
Preferably, the heat-transmitting element has a shape conformable to the shape of the transmitting and heating roller so as to facilitate the transmission of the thin films through the transmission passage. Accordingly, the heat-transmitting element can be an aluminum extrusion plate having a curved surface facing the transmitting and heating roller.
Preferably, the transmitting and heating roller includes an electro-heater for transforming electric energy into thermal energy; and a roller element disposed between the electro-heater and the second side of the transmission passage for transmitting the thermal energy from the electro-heater to the second one of the thin films.
For example, the electro-heater of the transmitting and heating roller is wrapped with the roller element, and transmits the thermal energy to the roller element in a manner of heat conduction. Alternatively, the electro-heater of the transmitting and heating roller is arranged outside the roller element and transmits the thermal energy to the roller element via a heat-diffusing element partially surrounding the roller element in a manner of heat radiation.
A second aspect of the present invention relates to a hot laminating apparatus for laminating thin films, which comprises a heating plate having a heater at a first free end and a heat-conducting plate at a second free end; and a transmitting and heating roller cooperating with the heat-conducting plate to clamp the thin films and rotating to move relative to the thin films so as to heat and laminate different area of the thin films.
Preferably, the heat-conducting plate is an aluminum extrusion plate.